Quantum cryptography leaves the lab

Article on the register thia morning giving some details of quantum crypto devices coming to the marketplace.

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Quantum cryptography - long the stuff of cyberpunk novels and hi-tech spy stories - is leaving the laboratory and making its way into commercial markets. A briefing session at the UK's Department of Trade and Industry on Wednesday featured demonstrations of working quantum key exchange systems by QinetiQ, Toshiba Cambridge and US start-up MagiQ.

Quantum cryptography allows two users on an optical fibre network to exchange secret keys. It takes advantage of the particle-like nature of light. In quantum cryptography, each bit of the key is encoded upon a single light particle (or ‘photon’). Intercepting this data randomly changes the polarisation of the light, irreversibly altering the data. Because of this quantum mechanics effect any attempt by an eavesdropper to determine a key corrupts the same key. Quantum cryptography systems discard these corrupt keys and only use codes that are known to be secure. These quantum keys, once exchanged, can be used in a one-time pad.

Advances in quantum computers or the discovery of advanced mathematical algorithms might one day threaten conventional scrambling techniques but quantum cryptography, properly implemented, is immune from such attacks.

Professor Andrew Briggs, head of Quantum Information Processing Interdisciplinary Research Collaboration at Oxford University, said that the UK had played a critical role in research into quantum cryptography. He urged the British government to do everything it can to make sure British companies profit from this pioneering work. "We've made a world leading contribution to the underlying science. Britain should also be at the forefront of developing applications."

Professor Brian Collins, professor of information systems at Cranfield University, agreed. "The initiative is passing from scientist to system designers to exploit this technology. We ignore it at our peril; it may become the only show in town."

Consultancy QIP, supported by the DTI, organised two seminars this week designed to promote understanding of the potential impacts of quantum cryptography to government officials, reps from the financial services and telecoms industry and the media. It provided a rare opportunity to see a range of systems at work. The event itself was well organised and mercifully free of the marketing hype that often comes with the introduction of new technology.

Live and direct
Toshiba Research Europe demoed a prototype system that applied quantum cryptography to the transmission of streaming video, an initiative that might one day open the door to ultra-secure video conferencing. The system allowed each frame of IP video, to be encrypted with a unique digital key, creating an unbreakable sequence of IP traffic. Toshiba Quantum Key Server produces up to 100 quantum keys per second. Toshiba’s team has already achieved a number of world firsts including the a new type of light emitting diode (LED) that fires out photons one at a time and an ultra-low noise single photon detector.

US start-up MagiQ has already begun selling systems based on its technology in the UK. Staff from UK reseller NOW Wireless were on hand to show how their kit added an extra layer of security on VPNs. Once secure keys are exchanged, data can be encrypted using standard protocols. QintiQ demo-ed its free-space quantum cryptography system. Ultimately its approach might allow quantum keys to be exchange via satellite.

Swiss firm ID Quantique, along with MagiQ, are the only companies selling quantum key distribution systems commercially. Target markets are governments and financial services. Quantum key exchange systems from MagiQ sell at between $70,000-$100,000, a small premium on conventional cryptographic systems.

Although expense is not a factor several limitations with quantum cryptography remain. Hackers can't break codes protected by quantum crypto but they might be able to disrupt communications. Quantum cryptography is limited to use between two dedicated points, or perhaps around a star network. It can't be routed because this process would interfere with the exchange of keys.

Stuart Brooklehurst, SVP at Visa International, pointed out that the absolute secrecy offered by quantum cryptography only referred to the transmission of data. "It’s not a total solution. Risks are at least as great in other parts of the system," he said.

The big play for quantum crypto in financial services is for applications like data recovery and links between wholesale banks. Brooklehurst pointed out that systems have to go through expensive upgrades when protocols are upgraded. Quantum crypto, though initially more expensive, would provide the ultimate in investment protection. ®

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Original story here:
http://www.theregister.co.uk/2005/04/28/quantum_crypto/

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The system allowed each frame of IP video, to be encrypted with a unique digital key, creating an unbreakable sequence of IP traffic

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The entire concept that anything is unbreakable reeks of nievety and ignorance. Anybody who claims a product to be "unbreakable" is either ignorant, a fraud, or both. Nothing is ubreakable.

I may not have any bright ideas on how to break it, but somebody sure will soon enough. I don't care how advanced it is, and I don't care if relies on Heisenberg's Uncertainty Principle. Simply because we don't know how to do it does not mean that it cannot be done.

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Nothing is ubreakable.

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I'm sorry, but I find that just as absurd as you find the origonal statement of it being unbreakable. Just because you have not found a system you could not break yet, just because someone has not found a code they could not break yet, does NOT mean that there is nver going to be a system of relative and logical thinking that would dissallow the capability of cracking by the very nature of it's design.

Stop thinking in terms of "mantra mantra mantra!" and start thinking in terms of non-extremism. People also said that speed beyond sound would be impossible due to the way they were origonally constructing the aircraft. They redesigned the idea of flight from the ground up, redid mathamathics, and achieved the once-thought impossible.

People need to stop saying "nothing is unbreakable", because it is as pointless and subjective since we can not forsee the future or future cryptographic algorithms that may come from a genius mind that extends beyond the capability of traditional thought. People need to start saying "So far, nothing has been unbreakable."

Sure there are realms of possibility that we cannot yet forsee. However, if it can be built, it can be broken--or rather, reverse engineered. That's pretty absolute.

However, in the realm of probabilities, and good sales practices--you can make such a claim if it can be properly substantiated by your product. Would you buy that birth control pill if it said, "Will probably prevent pregnancy" on the box? It's proven 99% effective, then you're 99% correct in your statement that it is in fact unbreakable. Right now, Quantum Cryptography holds the same standard, if not better. Relax, and enjoy a new triumph of technology and human achievement.

I thought (and I'm quite likely wrong) that quantum crypto provided the secure transmission of data or more specifically because individual photons were being used any attempt to intercept the transmission caused a change in the signal and any attempt would therefore be detected.

In the end it doesn't matter how good the encryption it still has to be decyphered at some point to be used and then you are back to the human problem. If you can get the users out the loop you'd be getting somewhere.

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However, if it can be built, it can be broken--or rather, reverse engineered. That's pretty absolute.

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Yet again, stop saying that we will never be able to go faster than the speed of sound. Even wanting to call "nothing can be unbreakable" an absolute is childish in the sense that you want to preassume that in NO future will there ever be a new invention that completley disables the capability of it being cracked. So please, for the sake of science and proper terminology, stop using that mantra of "nothing is unbreakable". Until you can predict the future and know that not a single brilliant mind will YET AGAIN be able to think outside the typical current-day realm of logic, then your "absolute" is premature and unfounded.

I'm not talking about an ubersystem with amazing cryptography. I'm talking about a system that uses a completely different line of logic and thinking for access that neither you or me can grasp right now, because it has not been shown to us.

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Yet again, stop saying that we will never be able to go faster than the speed of sound.

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You seem to be great at putting words into people's mouth which they have not utter at all.

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Until you can predict the future and know that not a single brilliant mind will YET AGAIN be able to think outside the typical current-day realm of logic, then your "absolute" is premature and unfounded

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Until you get in into your head that just maybe someday someone will find a way to break it than I would say that your logic is also "premature and unfounded."

Now I can see this thread being turning into a flamewar. Let's stop that before it starts, shall we?

Guardian's point was that it may be possible to build an unbreakable key exchange system. I don't believe he said that it is unbreakable; he was only advocating the possibility. This whole debate could besummed up as such:

Nothing is impossible. This includes both the successful compromise of cryptographic key exchange systems and the development of an unbreakable key exchange system.

Now while I agree on both points, I would like to think that I have learned the lessons of history. These lessons have taught us that all systems are breakable. Buuut... they have also taught us that nothing is impossible (there's that mantra again...).

Both points aside, never assume a system is unbreakable. Assume it is, and hope that it is not.

But please, let's avoid heating the debate to the point where personal attacks become a factor.

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Originally posted here by Striek
The entire concept that anything is unbreakable reeks of nievety and ignorance. Anybody who claims a product to be "unbreakable" is either ignorant, a fraud, or both. Nothing is ubreakable.

I may not have any bright ideas on how to break it, but somebody sure will soon enough. I don't care how advanced it is, and I don't care if relies on Heisenberg's Uncertainty Principle. Simply because we don't know how to do it does not mean that it cannot be done.

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We're (US.) retiring systems a few generations old, but those systems are so validated that they never need patching. Provably Secure, Kernelized Secure Operating System, TOS's... those terms come to mind when I read these statements. Why haven't Chinese and Pakistani hackers launched missiles, why haven't people launched missiles, why haven't air traffic controller towers been hacked, why haven't Metropolitan Transportation subways been hacked, why hasn't NORAD (Cheyenne Mt. CO,) systems been compromised, why hasn’t Eglin Air Force Base bunker-buster data systems been hacked, why haven't SOCOM (US DoD) systems been hacked, why hasn't Camp David been compromised, why hasn't top level Pentagon systems been compromised (because thehores13 is there ;) ), why hasn't .... Why, why, why? The only breaks I read about are lower level systems (C2) being compromised with data not worth securing.

Hi

Just a follow up: Interestingly, a network protected by simple quantum encryption[1] has been broken, as one can read at nature news[2].
Nevertheless, it is clear to the authors:

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Shapiro and Wong agree. And they add that a quantum cryptographic network can be simply tweaked to beat their attack. By making the key out of a lot of photons instead of just a few, the sender and receiver could ensure that the eavesdropper never got enough of the key to use it. Still, they say, the work shows that secrets — even quantum ones — are never entirely safe.

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Important for some of us: commercial systems, like the one by idQuantique[3] are not vulnerable to this attack.


Cheers

[1] http://arxiv.org/abs/quant-ph/0702202
[2] http://www.nature.com/news/2007/0704...070423-10.html
[3] http://idquantique.com/

So the real question is how many ways can we make imprints on a photon? xD
Brute force is probably not going to be added off-the-bat. You heard it here first.

Ok, the basic principle for quantum encryption relies on polarisation. A single photon vibrates in a single axis. Thus you can encode binary data on to photons by changing the axis of vibration. E.g. Vertical vibration is 1 and horizontal vibration is 0. You then detect the data by passing it through a vertical (or a horizontal) polaroid filter. If the photon is "1" it will pass through the filter and be recieved, if not it will be absorbed by the filter. Thus you build up a sequence of 1's and 0's.

Now the encryption bit. You change between encrypting on + axis and X axis at "random". Using | and / as 1, - and \ as 0. The receiving end knows your sequence of X and +, the key, and so can receive the data. Malice intercepting your data has to play a 50-50 guessing game with his polaroid filters. if he puts in a | filter and recieves a / photon there is a 50-50 chance that the photon will pass through the filter. Thus, every filter he gets wrong gives a 50% chance of receiving the wrong data. Additionally, when he sends the photon on he will encode the photon using the same axis as his filter, giving a 50-50 chance that Bob the recipient will receive the wrong data. In this way not only does Malice not intercept the correct message but Bob is very much aware of Malice's interference since the received message is corrupted.

Perhaps some day we will discover a way of identifying the vibration of a photon without destroying it, I don't deny that. The key point here is that the message is UNINTERCEPTABLE not UNDECRYPTABLE. Once you receive the message its no problem to decrypt it. In fact, its in the clear. But first you have to get the key (so, weakness right there....simply get the key).

Other points:
1) this requires a dedicated fibre line. If you have a dedicated fibre line between two points its difficult to evesdrop anyway. This is not something that gets sent over the net for anyone with a traffic sniffer in the right place to catch.

2) Its a bloody slow method of communicating. Sending single photons is slow especially allowing time for filter changes.

So yes, I do believe it is unbreakable encryption. I don't count getting the key as breaking the encryption. There is no way to "brute force" this. Its a laws of physics thing not a "10,000,000,000 years with the fastest PC ever" thing.